On its own, heat stroke qualifies as a medical emergency. When the overheated person has hepatitis C though, this adds an extra dimension to the problem. That's because a rare but serious complication of heat stroke is liver failure, which is crucial for people with hepatitis C to avoid.

“Heat stroke causes liver damage, or liver shock, because it decreases blood supply to your liver," says Anthony Michaels, MD, an assistant clinical professor of medicine and gastroenterology at the Ohio State Wexner Medical Center in Columbus. "It is important for people with hepatitis C to know about this danger."

However, Dr. Michaels says, "There's no evidence that having hepatitis C puts you at increased risk of getting heat stroke. But having hepatitis C might make heat stroke more dangerous for you."

How Heat Stroke Causes Liver Damage

Two types of heat stroke, according to the American Academy of Family Physicians, are exertional and non-exertional. Both can cause liver damage, but the exertional type develops more quickly. Exertional heat stroke is more likely to occur in a young, healthy person, whereas non-exertional heat stroke usually occurs in an older, sicker person exposed to heat over a longer period of time.

“A typical example of liver failure caused by exertional heat stroke would be a marathon runner, running in the heat and becoming dehydrated," says Carlos Romero-Marrero, MD, a liver disease specialist at the Cleveland Clinic. "Damage is not usually limited to the liver. Many organs can be damaged." In fact, he says, "only about 5 percent of these cases result in serious liver failure."

Liver damage and other organ damage occur when the amount of heat is more than the body can handle, and severe liver failure from heat stroke could be fatal, researchers reported in a study published in the journal Case Reports in Clinical Care in 2012.

“Severe heat stroke causes breakdown of muscle tissue," Dr. Romero-Marrero says. "Chemicals called inflammatory mediators may be released into the bloodstream, causing a severe drop in blood pressure, which leads to tissue damage from lack of blood."

Recognize Heat Stroke

If heat stroke is reversed at an early stage, survival is close to 100 percent. Symptoms of heat exhaustion — a milder form of heat illness that can precede heat stroke — include:

Dizziness

Fatigue

Headache

Nausea

Confusion

Hot, dry skin

Feeling flushed but not sweaty

Symptoms of the more severe heat stroke may include a high body temperature, loss of consciousness, seizure and rapid breathing.

At the first signs of heat exhaustion, you should get into a shaded area, lie down with your feet elevated, and cool your body with cold water and ice packs. If symptoms of heat exhaustion continue or become worse, call 9-1-1 or get to an emergency room.

Prevent Heat Exhaustion and Heat Stroke

“Whether you have hepatitis C or not, you should know how to prevent heat stroke," Michaels says. "You should drink plenty of fluids and avoid exercising in excessive heat."

Other prevention tips include:

Drink plenty of water or sports drinks to avoid dehydration in the heat.

Avoid caffeinated drinks and alcohol.

Wear lightweight, loose-fitting clothing and protecting yourself with a hat and sunglasses.

Take some time to adjust to the heat before exercising.

Take frequent breaks to drink, rest, and mist yourself with a spray bottle.

Schedule outdoor activities for morning or late afternoon instead of during the hottest time of the day.

Seek relief from the heat. Those who are elderly or disabled and indoors without air-conditioning should call for help. Many communities have special shelters that offer heat relief.

“We can’t say that having hepatitis C puts you at greater risk for or from heat stroke, but it makes sense to warn people with hepatitis C about this potential danger," Romero-Marrero says. "Knowing the dangers of heat stroke is something everyone can benefit from."